Visualizing the cost of health care

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This chart, which was published by National Geographic in 2009, illustrates the costs and results of medical care in different countries.

The left side of the chart shows where the country stands in per-person spending on health care, in relation to average spending. The right side of the chart shows where the country stands in life expectancy at birth, in relation to average life expectancy. An upward-sloping line indicates citizens of a country are getting good value for their medical care spending; a downward-sloping line indicates the opposite. The thickness of the line shows the number of doctor visits the average person makes in a year, a rough measure of the amount of medical care.

This type of chart was invented by Edward R. Tufte, regarded by many as the world’s leading expert on graphic presentation of information. He put one in his 1983 book, The Visual Display of Quantitative Information, but it never caught on.

Many commenters on the National Geographic web log criticized the chart. Oliver Uberti, who made the chart, responded by presenting the same information a different way, as shown below.

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In this chart, average life expectancy is plotted along a vertical axis. The higher a country on the charter, the longer its citizens live. Medical spending per person is plotted along a horizontal axis. The further to the right a country is, the more it spends per person on medical care. The size of the circle is proportional to the number of doctor visits the average person wants to make in a year.

The best position on this scatterplot chart is high and to the left; the best position on the line slope chart is low on the left and high on the right.

I think the first chart is by far the better. The steep downward slope of the United States from left to right catches the eye, as just the less steep but thicker upward slope of Japan. With the scatter chart, I have to stop and think what the vertical and horizontal axes measure. The size of the circles highlights the average number of doctor visits better than the sloping line chart, but I don’t think this is the most significant measure.

What do you think?

Click on The Cost of Care for the chart in its original context on the National Geographic Magazine web site.